1. Field of the Invention
The invention relates to a trailing arm suspension comprising a pair of trailing arm assemblies mounted to the frame rails of a vehicle and carrying an axle having ground engaging wheels. In one of its aspects, the invention relates to a trailing arm suspension module where the trailing arm assemblies are interconnected and prepositioned for installation so that the module can be directly installed to the vehicle as an integral unit.
2. Description of the Related Art
Heavy-duty vehicles such as semi-tractor/trailers typically have multiple trailing arm suspensions comprising a pair of trailing arm assemblies mounted to the vehicle or trailer frame and carrying an axle with ground engaging wheels. The axle can be either a drive axle or a non-drive axle. The trailing arm assemblies typically comprise a trailing arm having first and second ends. The first end is pivotally connected to a hanger bracket that is directly connected to the vehicle frame. The second end mounts one portion of an air spring having another portion mounted to the vehicle frame. The trailing arm is free to rotate about the pivotal connection with the hanger bracket and the air spring dampens the rotational movement of the trailing arm. The axle spans the opposing trailing arms and is secured to the trailing arms by suitable brackets. The trailing arm suspension can include other components such as shock absorbers and torsion rods, for example.
In all current trailing arm suspensions, the trailing arm assemblies and partial subassemblies of the other suspension components are built up on the vehicle. In other words, the trailing arm suspension is installed or mounted to the vehicle frame by sequentially mounting and interconnecting each of the components or partial subassemblies to each other on the vehicle frame as required. The build up approach to assembling and installing the trailing arm suspension requires a relatively long time and it is highly desirable to reduce the assembly time of the trailing arm suspension to reduce assembly costs.
The invention relates to a modular suspension adapted to mount on a vehicle frame having a pair of spaced C-shaped frame rails. The modular suspension comprises a pair of trailing arm assemblies connected by a cross beam and a trailing arm connection. Each of the trailing arm assemblies comprises a frame bracket adapted to be mounted to one of the frame rails and a trailing arm having one portion pivotally mounted to the frame bracket for pivotal movement about a pivot axis. The trailing arm connection extends between and is coupled to a portion of the trailing arms rearward of the pivot axis. The cross beam extends between and connects to the frame brackets such that a rail opening having a shape for slidably receiving at least a portion of one of the frame rails is formed between each of the frame brackets and the cross beam. The modular suspension can be mounted to the frame rails by aligning each of the frame rails with each of the rail openings and moving the modular suspension longitudinally relative to the frame rails.
The modular suspension further comprises a connector mounting each of the frame brackets to the cross beam. The connector can comprise a spacer mounted between a portion of the frame bracket and the crossbeam and a removable fastener secures the spacer to the frame bracket and cross beam.
The trailing arm connection can comprise an axle mounted to the trailing arms for movement therewith. The trailing arm connection can alternatively comprise a torque tube mounted to a portion of the trailing arms rearward of the pivot pin.
The frame rail opening is preferably L-shaped and slidably receives a portion of the frame rail.
The modular suspension can further comprise a spring adapted to operably connect the trailing arm to the vehicle frame for resisting the pivotal movement of the trailing arm about the pivotal axis toward the frame. A pair of shock absorbers can also be mounted to the modular assembly. Each of the shock absorbers has one end pivotally mounted to one of the trailing arms and the other end adapted to be mounted to one of the frame rails. A positioning bracket can extend between the other end of the shock absorber and the air spring to fix the position of the other end of the shock absorber in a position for mounting to the frame rail when the modular suspension is slidably mounted on the frame rails. A torsion torque rod extends from the axle to the cross beam and a lateral brace extends from the axle to one of the rails.
In another embodiment, the invention relates to a method for installing a modular suspension on a vehicle frame having a pair of spaced C-shaped frame rails. The modular suspension comprises a pair of trailing arm assemblies, each of which comprises a frame bracket and a trailing arm having one portion pivotally mounted to the frame bracket for pivotal movement about a pivot axis. A trailing arm connection extends between and is coupled to a portion of the trailing arms rearward of the pivot axis. A cross beam extends between and is connected to the frame brackets with a rail opening therebetween for slidably receiving at least a portion of one of the frame rails. The method comprises: aligning the frame rails with the rail openings, moving the modular suspension longitudinally relative to the frame rails to insert the rails into the rail openings, and affixing the cross beam and each of the frame brackets to the rails.